Adjustable multi-leg load-carrying sling apparatus

ABSTRACT

A multi-leg sling apparatus is presented for lifting loads having individual sling legs adjustable in length in a simple, and highly reliable manner to enable balanced and unbalanced loads to be supported in a variety of different orientations.

United States Patent. [1 1 Goodrich [451 Sept. 24, 1974 ADJUSTABLEMULTl-LEG LOAD-CARRYING SLING APPARATUS [76] Inventor: Donald B.Goodrich, 1935 Sandalwood, El Centro, Calif. 92243 [22] Filed: Dec. 18,1972 21 Appl. No.: 316,324

[52] US. Cl. 294/74, 294/78 A [51] Int. Cl. B66c 1/12 [58] Field ofSearch 294/74, 78 R, 78 A, 86 LS;

24/115 G, 115 H, 116 A, 126 C, 126 K, 126 L, 132 AS, 132 HL; 188/64;254/192 [56] References Cited UNITED STATES PATENTS 2,436,247 2/1948Bufflap 294/1 R 2,629,625 2/1953 Phillips 294/74 2,820,661 l/l958 Koonset al 294/74 X 2,919,949 l/1960 Caldwell 294/74 FOREIGN PATENTS ORAPPLICATIONS 955,824 4/1964 Great Britain 294/74 383,799 l/1965Switzerland 24/116 A Primary Examiner-Richard A. Schacher AssistantExaminer-Johnny D. Cherry Attorney, Agent, or Firm-R. S. Sciascia; G..1. Rubens [5 7] ABSTRACT A multi-leg sling apparatus is presented forlifting loads having individual sling legs adjustable in length in asimple, and highly reliable manner to enable balanced and unbalancedloads to be supported in a variety of different orientations.

3 Claims, 7 Drawing Figures ADJUSTABLE MULTI-LEG LOAD-CARRYING SLINGAPPARATUS STATEMENT OF GOVERNMENT INTEREST The invention describedherein may be manufactured and used by or for the Government of theUnited States of America for governmental purposes without the paymentof any royalties thereon or therefor.

BACKGROUND OF THE INVENTION This invention relates to lifting apparatus,and more particularly to a multi-leg sling apparatus in which each legcan be individually adjusted.

Various types of sling apparatuses have been proposed to accommodatedifferent loads under awide varietyof operational conditions. However,most of the prior art slings are limited in scope of application, andmany were designed to handle special load lifting situations. Selfequalizing slings have been advanced in which a single line is reevedaround a pulley or the like whereby either leg of the pair can beadjusted in length. Such slings adjust in only one plane, and since theentire load is assumed by only two legs a heavy steel cable or chain isrequired for many applications.

Multi-leg slings have been available wherein the individual lengths areadjusted by adding or subtracting a finite length to the leg segments,but such an arrangement is accident prone; andmost important it is tootime consuming for military operations, such as by helicopter hoistingor'conventional crane operations.

SUMMARY OF THE INVENTION The novel multi-leg sling apparatus provides asimple manner of adjusting each leg in an expedient manner to adapt thesling to support balanced andunbalanced loads over a wide range ofapplications. In the preferred embodiment, the sling comprises at leasttwo pairs of sling legs, each pair being fabricated of a continuouslength of flexible line supported intermediately by a saddle device,accordingly, each line provides a continuous and uninterrupted loadpath. The lines are disposed in a criss-cross relation so that theyconnect to diagonally opposite attach points on the load. Such anarrangement provides adjustment in two directions simultaneously withoutthe need to dispose of excess line or add to the line. The line ispreferably fabricated of flexible material having formed therein aplurality of spaced protuberances, suchas links, loops, beads, etc. Thelifting saddle supporting the legs at their confluence point has acorresponding recess or the like to receive a selected one of theprotuberances in each leg. Depending on the desired adjustment, clampingmeans are provided in the saddle for maintaining the selected adjustmentin the legs.

STATEMENT'OF THE OBJECTS A principal purpose of this invention is toprovide an adjustable multi-leg sling that can lift a'variety ofdifferent payloads having different centers of gravity in a variety oforientations in a simple and expedient manner.

Still another important object is to provide such a sling with a minimumof parts, joints, disconnects thus reducing weight, bulk and cost whilepossessing a high degree of safety, reliability and endurance.

Still further objects are to provide a sling which can be adjusted inroll and pitch without the need for disconnecting the sling from thepayload or the hoist hook; and to enable the sling line to be made of avariety of materials depending on the intended load capacity.

Other objects, advantages and novel features of the invention willbecome apparent from the following detailed description of the inventionwhen considered in conjuntion with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of thenovel slingshown lifting a balanced load in a level orientation achievedby adjusting all of the sling legs to be of equal length.

FIG. 2 is a perspective view of the novel sling shown lifting anunbalanced load in a level orientation, achieved by adjusting the lefthand legs to be longer than the right-hand legs.

FIG. 3 is a similar view of FIG. 1 showing a balanced load being raisedin an inclined position, achieved by adjusting the right-hand sling legsto be longer than the left hand legs. v

FIG. 4 is an enlarged side elevation view of one modification of alifting saddle, partially in section, in an open position to receive asling line having aspaced swagged balls to be clamped by the saddle.

FIG. 5 is an enlarged front elevation of another modification of alifting saddle adapted to receive a sling line having chain links.

FIGS. 6 and 7 are perspective views of modified sling lines that can beemployed.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing wherelike reference numerals refer to similar parts throughout thedrawing,.there is showon in FIGS. 1 to 3, inclusive, a novel multi-legsling apparatus 10 supporting suspended loads l2, l4 and 16 of differingcharacteristics, these being only representative of some of the varioustypes of loads to which the sling may be adapted. In FIG. 1, load 12 isa balanced load, as indicated by symbol l7, beingsuspended in a levelcondition by adjusting the lengths of sling legs, 18a, 18b, 20a, and 20bto be of equal length, four legs being illustrated. In FIG. 2, load 14is'unbalanced but suspended in a level condition by making sling legs18a and 20a of equal length but longer than legs 18b and 20b. In FIG. 3balanced load 16 is suspended in a canted position by making legsl8a-and 20a shorter in length than legs 18b and 20b.

Variable control over the lifting of balanced and unbalanced loads invarious orientations is' achieved by using at least two pairs of slinglegs, 18a, 18b, and 20a, 20b, each pair of legs being formed of singleflexible line, namely 18 and 20 of identical length. The lines areadjustably supported intermediately their ends by a novel saddle fixture22, shown in detail in FIGS. 4 and 5, which enables the respective legsto be varied in length. In the preferred embodiment, the lines 18 and 20are arranged in criss-cross orientation with saddle 22 supporting thelines at their confluence point. By such a configuration, a continuous,uninterrupted load path is provided in each line without the use ofsplices,

joints, etc.

and by providing saddle 22 with compatible means for engaging andlocking the respective sling legs at selected locking elements thereinto provide the desired length. The entire length of sling lines 18 and20 need not be provided with locking elements 24 as shown in FIGS. 1through 3 since only those portions of the legs adjacent both sides ofsaddle fixture 22 that afford the necessary degree of adjusting may beprovided with the protuberances. In the modification illustrated in FIG.4,

saddle 25 comprises an inverted U-shaped bolt 26 on which is freelythreaded three spaced apart plates 28, 30, and 32 secured thereon bynuts 34. Plates 30 and e e s neetanfl ws ,jaws,rs sstiYslxrleydepressions on their opposing faces to receive the protuberances 24.Jaws 30 and 32 are biased to an engaging position by a compressionspring 36. In FIG. 4 the jaws are shown spread apart to slidably receivetherebetween sling legs 18a and 18b, only one line 18 being shown forclarity, although it should be under stood that both lines 18 and 20intersect between jaws 30 and 32, and, accordingly, depressions 35 aresimilarly arranged in corresponding crossing relation.

In the modification of FIG. 4, lines 18 and 20 are fabricated with metalballs 38 much like conventional fishing line weights, which are swaggedor otherwise securely fixed to the line in spaced relation. Theoperation of saddle 25 is apparent from the drawings. The length of theindividual sling legs are adjusted in accordance with the liftingrequirements, and their selected position locked within saddle 25 byreleasing spring 36, making sure that balls 38 are seated in theircorresponding recess 35. The mating of balls 38 and recesses 35 preventany axial movement in the lines. Thereafter the lengths of the slinglegs can be quickly adjusted by unlocking the saddle and repositioningthe legs axially therein without the necessity of adding lengths ofline, or disconnecting the lines from the load or the saddle hook.

Another type of saddle fixture 40 shown in FIG. 5 is adapted toadjustably receive a line having a series of spaced, chain-like lockingelements formed along its length. In FIG. 5 the locking elements areillustrated as conventional metal chain links 42 which may be requiredfor hoisting high-tonnage loads. For light loads, the links may beformed of two strands 43 and 44 of braided polypropylene linealternately threaded one through the other to form consecutive loops, asillustrated in FIG. 7. Still another type of linked line is shown inFIG. 6, wherein the loops are formed in two parallel metal wires 46 and48 by means of metal sleeves 50 swagged or otherwise secured around bothwires at spaced locations along selected lengths of the wires.

In FIG. 5, saddle 40 also comprises an inverted U- shaped bolt 52 onwhich are freely threaded two spaced plates, upper plate 54 and lowerplate 56 secured on the bolt by nuts 58. An anchor bolt 60 is centrallymounted in one of the plates, i.e., the upper plate in the modificationof FIG. 5. A free end of bolt 60 is adapted to engage an opening 62 inthe lower plate. Bolt.60 is designed to be passed through selected linksof each chain leg for anchoring the legs at the desired length.

Plate 54 is maintained in a fixed relation to plate 56,

with the threaded links anchored therebetween, by a pair of latches 64,pivotally mounted to plate 54 and adapted to hook over the ends of plate56. Readjustment of the lengths of the sling legs is accomplishedsimply, by releasing latches 64, lifting anchor bolt out of the lowerplate and longitudinally moving the legs to their new position. As inthe prior saddle modification, adjustment is accomplished withoutreleasing the sling from the load or from the saddle, and without addingor removing additional components.

The invention sling offers numerous advantages over prior art devices inits simplicity in design and operation. The novel sling can be appliedto a wide range of load capacities, enabling a choice of different slingleg material and configuration depending on the specific use. The fourslings are fabricated of two identical lengths of line having spacedprotuberances simplifying fabrication. Use of four legs in diagonalorientation provides adjustment in two directions to handle roll andpitch movements. The sling legs are detachably supported and restrainedat their confluence by a single attachment in a positive mannerpreventing undue movement of the load or transit. The length of thesling legs can be easily changed by relatively inexperienced personnelwithout having excess line material to dispose or, or the adding ofadditional lengths of line by means of connectors, etc.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

What is claimed is:

1. An adjustable load-carrying sling apparatus comprising:

at least two pairs of flexible sling legs having means at their lowerends for attachment to a load;

each pair of sling legs being fabricated of a single length ofcontinuous and uninterrupted flexible line material arranged incriss-cross relation at intermediate portions thereof;

each leg having a plurality of locking elements fixedly secured atvspaced-apart positions along at least a selected portion of its length;

a lifting saddle member for supporting both lengths of flexible materialat their intermediate criss-cross positions forming at least four slinglegs;

a means for locking the saddle to any selected one of said elements onboth of said sling legs where they criss-cross for varying the length ofthe respective legs;

whereby the individual lengths of the sling legs can be readily adjustedand positively locked in position to accommodate different. orientationsof the load along two transverse axes.

2. An adjustable load-carrying sling apparatus comprising:

at least two pairs of flexible sling legs having means at their lowerends for attachment to a load;

each pair of legs being fabricated of a single length of continuous anduninterrupted flexible line material;

said pairs of legs being arrangedin criss-cross relation at intermediateportions;

each leg having a plurality of looped elements fixedly secured atspaced-apart positions along at least a selected portion of its lengthforming the flexible line;

a lifting saddle member for supporting said pairs of legs at theirintermediate positions forming at least four sling legs;

said saddle having a single pin adjustably positioned through a selectedlooped element in each pair of legs at their criss-crossed portions;

whereby the individual lengths of the sling legs can be 3. The slingapparatus of claim 2 wherein each of said flexible lines are formed ofat least two strands of braided material which are alternately threadedreadily adjusted and positively locked in position to 5 through eachother to form the loops-

1. An adjustable load-carrying sling apparatus comprising: at least twopairs of flexible sling legs having means at their lower ends forattachment to a load; each pair of sling legs being fabricated of asingle length of continuous and uninterrupted flexible line materialarranged in criss-cross relation at intermediate portions thereof; eachleg having a plurality of locking elements fixedly secured atspaced-apart positions along at least a selected portion of its length;a lifting saddle member for supporting both lengths of flexible materialat their intermediate criss-cross positions forming at least four slinglegs; a means for locking the saddle to any selected one of saidelements on both of said sling legs where they criss-cross for varyingthe length of the respective legs; whereby the individual lengths of thesling legs can be readily adjusted and positively locked in position toaccommodate different orientations of the load along two transverseaxes.
 2. An adjustable load-carrying sling apparatus comprising: atleast two pairs of flexible sling legs having means at their lower endsfor attachment to a load; each pair of legs being fabricated of a singlelength of continuous and uninterrupted flexible line material; saidpairs of legs being arranged in criss-cross relation at intermediateportions; each leg having a plurality of looped elements fixedly securedat spaced-apart positions along at least a selected portion of itslength forming the flexible line; a lifting saddle member for supportingsaid pairs of legs at their intermediate positions forming at least foursling legs; said saddle having a single pin adjustably positionedthrough a selected looped element in each pair of legs at theircriss-crossed portions; whereby the individual lengths of the sling legscan be readily adjusted and positively locked in position to accommodateload lifting conditions.
 3. The sling apparatus of claim 2 wherein eachof said flexible lines are formed of at least two strands of braidedmaterial which are alternately threaded through each other to form theloops.